This invention relates to a process for improving the recovery of phenol from aqueous phenolic mixtures by distillation. More particularly, it relates to avoiding the normal phenol-water azeotropic limitation by introducing an organic mixture into the overhead section of a distillation column used to separate phenol-water mixtures. In a more particular aspect of the invention, the organic mixture comprises benzene or lower alkyl substituted benzenes in admixture with lower ketones.
In fractionally distilling phenol-water mixtures in the normal way, the vapor composition in the overhead vapor fraction of the distillation column is limited by the normal phenol-water azeotropic limitation. This is the case because phenol and water form a minimum boiling azeotrope under fractional distillation conditions. This, of course, means that, in general, one cannot satisfactorily separate phenols from water from phenolic water mixtures by a conventional fractional distillation. The separation of materials by fractional distillation is normally a convenient and effective manner in which to separate materials. Consequently, there is a need to improve the normal fractional distillation of phenol-water mixtures in a manner which avoids the azeotropic compositional limitation.
It is an object of this invention to provide an improved distillation process for separating phenol from water. Other objects and the accomplishment thereof will be clear from the description to follow.